The proposed work, as has our previous work, will be concerned with the role of behavioral stress in the etiology of hypertension and related cardiovascular diseases. We have identified a group of young adult humans who when stressed by conditions which require active coping elicit an apparent excessive sympathetic drive on the heart. Such excessive sympathetic drive has been hypothesized to be relevant in the etiology of early or borderline hypertension but has not been preveiously observed to be associated with behavioral stressors in humans. Our current and proposed work seeks to determine further the significance of this behaviorally induced sympathetic effect. This will involve: (1) Determining in both humans and chronically prepared dogs whether this sympathetic effect is excessive or maladaptive relative to metabolic requirements, i.e., O2 consumption. (2) Determining when evoked in a chronically prepared dog whether renal functioning is compromised. (3) Ascertaining in the most reliable manner possible in humans a non-invasive means to evaluate sympathetic influences on myocardial performance that can be used in both the laboratory and field. (4) Determining whether individuals who demonstrate such effect; (a) do so with more naturalistic stressors that can be encountered in the lab and field; (b) demonstrate a more labile blood pressure; (c) can be differentiated from less reactive individuals with respect to blood pressure, coping styles, and a family history of cardiovascular disease. This is all intended to justify the initiation of a longitudinal study which will enable us in the most definitive way possible to ascertain the significance of excessive sympathetic myocardial drive.